Process for removal of alkynes and/or dienes from an olefin stream

ABSTRACT

The present invention is a process for removing alkynes and/or dienes from an olefin product stream withdrawn from an oxygenate-to-olefins reactor. The process comprises hydrogenating a first olefin stream that has alkynes and/or dienes in the presence of excess hydrogen and a first hydrogenation catalyst. The hydrogenation of the first olefin stream produces a second olefin stream that has unreacted hydrogen. The second olefin stream is contacted with a second hydrogenation catalyst producing a third olefin stream. The third olefin stream has low levels of hydrogen and alkynes and/or dienes.

FIELD OF THE INVENTION

The present invention relates to a process for removal of alkynes and/ordienes from an olefin stream, particularly an olefin stream from anoxygenate-to-olefins reaction.

BACKGROUND OF THE INVENTION

Olefins are traditionally produced from petroleum feedstock by catalyticor steam cracking processes. These cracking processes, especially steamcracking, produce prime olefins such as ethylene and/or propylene from avariety of hydrocarbon feedstock. Ethylene and propylene are importantcommodity petrochemicals useful in many processes for making plasticsand other chemical compounds. Ethylene is used to make variouspolyethylene plastics, and in making other chemicals such as vinylchloride, ethylene oxide, ethylbenzene and alcohol. Propylene is used tomake various polypropylene plastics, and in making other chemicals suchas acrylonitrile and propylene oxide.

The petrochemical industry has known for some time that oxygenates,especially alcohols, can be converted into prime olefins. This processis referred to as the oxygenate-to-olefin process. The preferredoxygenate for prime olefin production is methanol. The process ofconverting methanol-to-olefins is called the methanol-to-olefinsprocess.

There are numerous technologies available for producing oxygenates, andparticularly methanol, including fermentation or reaction of synthesisgas derived from natural gas, petroleum liquids, carbonaceous materialsincluding coal, recycled plastics, municipal waste or any other organicmaterial. The most common process for producing methanol is a two-stepprocess of converting natural gas to synthesis gas. Then, synthesis gasis converted to methanol.

Generally, the production of synthesis gas involves a combustionreaction of natural gas, mostly methane, and an oxygen source intohydrogen, carbon monoxide and/or carbon dioxide. Synthesis gasproduction processes are well known, and include conventional steamreforming, autothermal reforming or a combination thereof.

Synthesis gas is then processed into methanol. Specifically, thecomponents of synthesis gas (i.e., hydrogen, carbon monoxide and/orcarbon dioxide) are catalytically reacted in a methanol reactor in thepresence of a heterogeneous catalyst. For example, in one process,methanol is produced using a copper/zinc oxide catalyst in awater-cooled tubular methanol reactor.

The methanol is then converted to olefins in a methanol-to-olefinsprocess and produces a reactor effluent stream. The reactor effluentstream contains desirable olefin product as well as byproducts. Thebyproducts are typically removed from any olefin product stream to makeolefin product streams that are of an acceptable level of purity. Commonbyproducts in a methanol-to-olefin reactor effluent stream includeseveral alkynes and/or dienes. Examples of alkynes and/or dienesinclude, but are not limited to, acetylene, methyl acetylene andpropadiene. Alkynes and/or dienes are converted to olefins by ahydrogenation reaction. In a hydrogenation reaction, equimolar amountsof hydrogen and alkynes and/or dienes are reacted to produce a mole ofolefin. The hydrogenation of olefin is a competing reaction wherebyequimolar amounts of hydrogen and olefin are converted to a mole ofparaffin. The reaction of alkyne to olefin is desirable because iteliminates an impurity, specifically the alkyne. The competing reactionis not desirable because it converts prime olefin product to lessdesirable paraffin byproduct.

Hydrogen, a reactant in the hydrogenation reaction, is often added tothe alkyne containing olefin product stream to facilitate the reaction.Hydrogen is an impurity. Moreover, hydrogen often contains methane, COand CO₂. Likewise, these impurities can contaminate the olefin productstream, even when the hydrogenation reaction consumes all of thehydrogen. An added step of fractionation (typically a stripper) isrequired after hydrogenation to remove, excess hydrogen, methane, carbonmonoxide and/or carbon dioxide from the olefin product stream afterhydrogenation.

It would be desirable to have a hydrogenation step to eliminate alkynesand/or dienes that would result in an olefin product stream that hasacceptable levels of alkynes and/or dienes, hydrogen, methane, carbondioxide and/or carbon monoxide without the need for an additionalfractionation step. It would likewise be desirable to hydrogenate asmuch of the alkynes and/or dienes as possible while hydrogenating aslittle olefin as possible. The present invention satisfies these andother needs.

SUMMARY OF THE INVENTION

The present invention is a process for removing byproducts selected fromthe group comprising alkynes, dienes and mixtures thereof from an olefinproduct stream withdrawn from an oxygenate-to-olefins reactor. Theprocess comprises hydrogenating a first olefin stream that containsolefins and byproducts. The hydrogenating occurs in the presence ofexcess hydrogen and a first hydrogenation catalyst. For the purpose ofthis document, excess hydrogen means more than equamolar amounts ofhydrogen compared to the total moles of such byproducts. The processproduces a second olefin stream that has unreacted hydrogen. The secondolefin stream is contacted with a second hydrogenation catalystproducing a third olefin stream. The third olefin stream has less thanspecification levels of hydrogen and such byproducts. By specificationlevels it is meant the maximum amount of a byproduct that is toleratedin an olefin product that is used for a particular application or use.In one embodiment, the third olefin stream comprises 10 mppm or lesshydrogen and about 1 mppm or less of such byproducts based upon thecomposition of the third olefin stream.

In another embodiment, there is a process for making a polyolefinproduct from an oxygenate feed stream. The process begins by contactingan oxygenate feed stream with a molecular sieve catalyst in anoxygenate-to-olefin reactor. The contacting step produces a first olefinstream having olefins and byproducts selected from the group comprisingalkynes, dienes and mixtures thereof. The quantity of such byproducts inthe first olefin stream is about 200 mppm or less of such byproducts forevery mole of olefin in the first olefin stream. Typically, excesshydrogen is added to the first olefin stream. The mole ratio of hydrogento such byproducts in the first product stream is about 1.05:1 orgreater. The first olefin stream is hydrogenated in the presence of afirst hydrogenation catalyst producing a second olefin stream. Thesecond olefin stream comprises olefins and unreacted hydrogen. Thesecond olefin stream is contacted with a second hydrogenation catalystproducing a third olefin stream. The third olefin stream has about 10mppm or less hydrogen based upon the composition of the third olefinstream. The third olefin stream, then, is converted to the polyolefinproduct. In a certain embodiment about 1 mppm or less olefins, basedupon the total amount of olefins in the first olefin stream arehydrogenated in the foregoing process.

In another embodiment, there is a process for producing an ethylenestream from an oxygenate feed stream. The process comprises the step ofcontacting the oxygenate feed stream with a molecular sieve catalyst ina reactor. The contacting step produces a first olefin stream havingethylene, higher boiling point compounds and acetylene. The term “higherboiling point compounds” as it refers to ethylene means compounds with aboiling point higher than ethylene. A majority of the ethylene and amajority of the acetylene are separated from a majority of the higherboiling point compounds producing a first ethylene stream. The firstethylene stream is hydrogenated in the presence of excess hydrogenproducing a second ethylene stream. The second ethylene stream comprisesunreacted hydrogen. The unreacted hydrogen in the second ethylene streamis reacted to produce a third ethylene stream. The third ethylene streamhas about 10 mppm or less hydrogen based upon the composition of thethird ethylene stream. Moreover, about 1 mol. % or less of the ethylenein the first olefin stream is hydrogenated, based upon the amount ofethylene in the first ethylene stream.

In another embodiment, there is a process for producing a propylenestream from an oxygenate feed stream. The process comprises the step ofcontacting the oxygenate feed stream with a molecular sieve catalyst ina reactor. The contacting produces a first olefin stream havingpropylene, higher boiling point compounds or lower boiling pointcompounds and byproducts selected from the group comprising methylacetylene, propadiene and mixtures thereof The term “higher boilingpoint compounds” as it refers to propylene means compounds with aboiling point higher than propylene. The term “lower boiling pointcompounds” as it refers to propylene means compounds with a boilingpoint lower than propylene. A majority of the propylene and a majorityof said byproducts are separated from a majority of the higher boilingpoint compounds or lower boiling point compounds producing a firstpropylene stream. The first propylene stream is hydrogenated in thepresence of excess hydrogen producing a second propylene stream. Thesecond propylene stream comprises unreacted hydrogen. The unreactedhydrogen in the second propylene stream is reacted to produce a thirdpropylene stream. The third propylene stream has less than 10 mppmhydrogen based upon the composition of the third propylene stream.Moreover, no more than 1 mol. % of the propylene in the first olefinstream is hydrogenated in the previous hydrogenation steps, based uponthe amount of propylene in the first propylene stream.

In another embodiment, there is a process for hydrogenating byproductsconsisting of alkynes, dienes and mixtures thereof in an olefin productstream from an oxygenate-to-olefin reactor. The process comprisesproviding an olefin stream comprising byproducts and olefin selectedfrom the group consisting of ethylene, propylene and mixtures thereof.Excess hydrogen is added to the olefin stream. At least a portion of theexcess hydrogen is from a hydrogen source stream that has about 0.2 mol.% or less CO₂ and/or CO and has about 10 mol. % or less methane. Theolefin stream is hydrogenated to produce a hydrogenated olefin stream.The hydrogenated olefin stream has about 20 mppm or less hydrogen basedupon the composition of the hydrogenated olefin stream. Optionally, thehydrogenated olefin stream is fractionated to remove methane.

According to one or embodiments including those previously set forth, atleast a portion of the excess hydrogen is from a hydrogen source stream.The hydrogen source stream has about 90 mol. % or more, 95 mol. % ormore or about 98 mol. % or more hydrogen based upon the composition ofthe hydrogen source stream.

According to one or more embodiments including those previously setforth, a combined stream of the first olefin stream and the hydrogensource stream has about 500 mppm or less methane based upon thecomposition of the combined stream. Additionally or optionally, acombined stream of the first olefin stream and the hydrogen sourcestream has about 1 mppm or less CO based upon the composition of thecombined stream. Additionally or optionally, the combined stream of thefirst olefin stream and the hydrogen source stream has about 1 mppm orless CO₂ based upon the composition of the combined stream. Moreover,the first olefin stream has about 1 mppm or less CO₂ based upon thecomposition of the first olefin stream in one embodiment.

In yet another embodiment, including one or more of the embodimentspreviously disclosed, the excess hydrogen is present in the first olefinstream or combined stream, preferably about 1.05 moles or more ofhydrogen, more preferably about 1.5 moles to about 50 moles of hydrogenmore preferably from about 1.5 moles to about 10 moles of hydrogen arepresent for every mole of such byproduct in the respective first olefinstream or combined stream.

In yet another embodiment that encompasses one or more of theembodiments previously discussed, the hydrogen source stream is from asource selected from the group comprising pipeline hydrogen, hydrogenfrom reformed naphtha, hydrogen from refinery streams, hydrogen frombottled sources, hydrogen from water electrolysis reactors, hydrogenfrom refinery streams and hydrogen from decomposition of oxygenates suchas methanol.

In yet another embodiment that encompasses one or more of theembodiments previously discussed, the first olefin stream is heated.Typically, the first olefin stream is heated with the third olefinstream in a heat exchanger. Preferably, the first olefin stream isheated to a temperature ranging from about 100° F. (38° C.) to about250° F. (121° C.)—more preferably from about 120° F. (49° C.) to about200° F. (93° C.), most preferably from about 150° F. (66° C.) to about190° F. (88° C.).

In yet another embodiment, including one or more embodiments selectedfrom the embodiments disclosed above, the first hydrogenation stepoccurs at a pressure ranging from about 50 psia (344 kPaa) to about 400psia (2760 kPaa), preferably from about 200 psia (1380 kPaa) to about300 psia (2070 kPaa), more preferably from about 250 psia (1720 kPaa) toabout 300 psia (2070 kPaa).

In another embodiment in combination with one or more of the embodimentsselected above, the first catalyst is an elemental Group VIII metalcatalysts. Preferably, the first catalyst is an elemental noble metal ona substrate comprising silica, alumina and mixtures thereof with aco-catalyst selected from the group consisting of elemental silver,vanadium, iodine and combinations thereof. More preferably, the firstcatalyst is an elemental palladium catalyst. Most preferably, the firstcatalyst is an elemental palladium catalyst on a substrate selected fromthe group comprising alumina, silica and mixtures thereof with aco-catalyst selected from the group consisting of elemental silver,vanadium, iodine and combinations thereof.

In one or more embodiments disclosed above the process alternatively oroptionally has a first olefin stream that contains about 50 mol. % ormore, preferably about 90 mol. % or more, more preferably about 98 mol.% or more olefin based upon the composition of the first olefin stream.Optionally or alternatively, the first olefin stream comprises about 200mppm or less alkynes and or dienes.

In another embodiment that is in combination with one or more of theembodiments disclosed above, the first olefin stream contains about 25mol. % or more, preferably about 90 mol. % or more, more preferablyabout 98 mol. % or more ethylene based upon the composition of the firstolefin stream. Optionally or alternatively, thy byproducts includeacetylene. The first olefin stream comprises about 500 mppm or less,preferably about 200 mppm or less byproducts based upon the compositionof the first olefin stream.

In another embodiment that is in combination with one or more of theembodiments disclosed above, the first olefin stream contains about 25mol. % or more, preferably about 90 mol. % or more, more preferablyabout 98 mol. % or more propylene based upon the composition of thefirst olefin stream. Optionally or alternatively, the byproducts areselected from the group comprising methyl acetylene, propadiene andmixtures thereof. The first olefin stream comprises about 500 mppm orless, preferably about 200 mppm or less such byproducts based upon thecomposition of the first olefin stream.

In yet another embodiment that encompasses one or more of theembodiments previously discussed, the second olefin stream is heated.Preferably, the second olefin stream is heated to a temperature rangingfrom about 100° F. (38° C.) to about 250° F. (121° C.)—more preferablyfrom about 120° F. (49° C.) to about 200° F. (93° C.), most preferablyfrom about 150° F. (66° C.) to about 190° F. (88° C.).

In yet another embodiment, including one or more embodiments selectedfrom the embodiments disclosed above, the second hydrogenation stepoccurs at a pressure ranging from about 50 psia (344 kPaa) to about 400psia (2760 kPaa), preferably from about 200 psia (1380 kPaa) to about300 psia (2070 kPaa), more preferably from about 250 psia (1720 kPaa) toabout 300 psia (2070 kPaa).

In another embodiment in combination with one or more of the embodimentsselected above, the second catalyst is an elemental Group VIII metalcatalysts. Preferably, the second catalyst is an elemental noble metalon a substrate comprising silica alumina and mixtures thereof with aco-catalyst selected from the group consisting of elemental iron,elemental nickel and mixtures thereof. More preferably, the secondcatalyst is an elemental palladium catalyst. Most preferably, the secondcatalyst is an elemental palladium catalyst on substrate selected fromthe group comprising silica, alumina and mixtures thereof with aco-catalyst selected from the group consisting of elemental iron,elemental nickel and mixtures thereof. In one embodiment, the firstcatalyst is the same as the second catalyst. Preferably the firsthydrogenation step occurs in a first bed of a reactor vessel and thesecond hydrogenation step occurs in a second bed of a reactor vessel.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates the overall process of an oxygenate-to-olefins plantaccording to one embodiment of the present invention.

FIG. 2 is a process flow diagram illustrating an embodiment of thehydrogenation process according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION Introduction and Overview

To aid in the understanding of the present invention, a brief overviewof the stages of producing and using one or more olefin products from anoxygenate feed stream is discussed with reference to FIG. 1. Theoxygenate-to-olefin reaction stage 10 occurs in an oxygenate-to-olefinreactor and converts an oxygenate feed stream into a gaseous outputstream comprising one or more olefin(s). The gaseous output stream of anoxygenate-to-olefin reactor is defined as the effluent stream. Thereactor effluent stream is particularly the gaseous output stream fromthe point this stream leaves the reactor to the point the stream entersa quench device.

Following the oxygenate-to-olefin reaction stage, the reactor effluentstream passes through an effluent quenching stage 12. The effluentquenching stage 12 cools the reactor effluent stream and removes waterand catalyst fines from the reactor effluent stream. Included in theeffluent quenching stage 12 is optional compression of the quenchedeffluent stream.

The quenched effluent stream then undergoes a washing and drying stage14 to produce a dried effluent stream. Washing the quenched effluentstream removes acid components of the effluent stream, such as CO₂.Drying removes water that is saturated in the quenched effluent stream.Optionally, the washing and drying stage includes processing steps toremove additional oxygenates.

The dried effluent stream then undergoes an olefin product recoverystage 16. Particularly, prime olefins, i.e. ethylene, propylene, andbutylene are recovered in olefin product streams in acceptable grades ofpurity for their particular applications or end uses. In the productrecovery stage 16, alkynes and/or dienes such as acetylene or methylacetylene and/or propadiene is removed from an olefin stream accordingto one embodiment of the invention that is illustrated in FIG. 2. Asused herein, “and/or” as it pertains to one or more compositions isdefined as any composition comprising one of the compositions and anycombination or mixture of the one or more compositions.

Finally, the olefin product streams pass through an olefin product usestage 18. In the olefin product use stage 18, the particular olefinproduct streams are used in a polymerization process to make polyolefinproducts in one embodiment. For a more complete understanding of theintegrated process of producing and using olefin product streams from anoxygenate feed stream is discussed below in greater detail.

The Oxygenate-to-Olefin Reaction

An oxygenate feed stream is fed into an oxygenate-to-olefin reactorproducing a reactor effluent stream. The oxygenate-to-olefin reactor isa reactor that uses a catalyst and particularly a molecular sievecatalyst to convert an oxygenate to an olefin. A molecular sievecatalyst is a catalyst made of a molecular sieve material as set forthherein. Molecular sieve catalysts are useful for converting a feedstream that contains one or more aliphatic-containing compounds. The oneor more aliphatic-containing compounds include alcohols, amines,carbonyl compounds for example aldehydes, ketones and carboxylic acids,ethers, halides, mercaptans, sulfides, and the like, and mixturesthereof. The aliphatic moiety of the aliphatic-containing compoundstypically contains from 1 to about 50 carbon atoms, preferably from 1 to20 carbon atoms, more preferably from 1 to 10 carbon atoms, and mostpreferably from 1 to 4 carbon atoms.

Non-limiting examples of aliphatic-containing compounds include:alcohols such as methanol and ethanol, alkyl-mercaptans such as methylmercaptan and ethyl mercaptan, alkyl-sulfides such as methyl sulfide,alkyl-amines such as methyl amine, alkyl-ethers such as dimethyl ether,diethyl ether and methylethyl ether, alkyl-halides such as methylchloride and ethyl chloride, alkyl ketones such as dimethyl ketone,formaldehydes, and various acids such as acetic acid.

In a preferred embodiment of the process of the invention, the feedstream is an oxygenate feed stream. Particularly, an oxygenate feedstream is a feed stream that comprises one or more organic compound(s)containing at least one oxygen atom. In the most preferred embodiment ofthe invention, the oxygenate in the oxygenate feed stream is one or morealcohol(s), preferably aliphatic alcohol(s) where the aliphatic moietyof the alcohol(s) has from 1 to 20 carbon atoms, preferably from 1 to 10carbon atoms and most preferably from 1 to 4 carbon atoms. The alcoholsthat are useful in the oxygenate feed stream include lower straight andbranched chain aliphatic alcohols and their unsaturated counterparts.

Non-limiting examples of oxygenates include methanol, ethanol,n-propanol, isopropanol, methyl ethyl ether, dimethyl ether, diethylether, di-isopropyl ether, formaldehyde, dimethyl carbonate, dimethylketone, acetic acid, and mixtures thereof.

In the most preferred embodiment, the oxygenate feed stream comprisesoxygenates selected from one or more of methanol, ethanol, dimethylether, diethyl ether or a combination thereof, more preferably methanoland dimethyl ether, and most preferably methanol.

In one embodiment, the oxygenate feed stream is produced from anintegrated process for producing oxygenates, particularly alcohols, froma hydrocarbon feedstock, preferably a hydrocarbon gas feedstock, morepreferably methane and/or ethane. The first step in the process ispassing the gaseous hydrocarbon feedstock, preferably in combinationwith a water stream, to a synthesis gas production zone to produce asynthesis gas stream containing synthesis gas. Synthesis gas productionis well known, and typical synthesis gas temperatures are in the rangeof from about 700° C. to about 1200° C. and synthesis gas pressures arein the range of from about 2 MPa to about 100 MPa. Synthesis gas streamsare produced from natural gas, petroleum liquids, and carbonaceousmaterials such as coal, recycled plastic, municipal waste or any otherorganic material, preferably synthesis gas stream is produced via steamreforming of natural gas.

Generally, a heterogeneous catalyst, typically a copper based catalyst,is contacted with a synthesis gas stream, typically carbon dioxide andcarbon monoxide and hydrogen to produce an alcohol, preferably methanol,often in combination with water. In one embodiment, the synthesis gasstream at a synthesis temperature in the range of from about 150° C. toabout 450° C. and at a synthesis pressure in the range of from about 5MPa to about 10 MPa is passed through a carbon oxide conversion zone toproduce an oxygenate containing stream.

This oxygenate containing stream, or crude methanol, typically containsthe alcohol product and various other components such as ethers,particularly dimethyl ether, ketones, aldehydes, dissolved gases such ashydrogen methane, carbon oxide, nitrogen, and fusel oil. The oxygenatecontaining stream, crude methanol, in the preferred embodiment is passedthrough a well known purification processes, distillation, separationand fractionation, resulting in a purified oxygenate containing stream,for example, commercial Grade A and AA methanol. This purified oxygenatecontaining stream is used in one embodiment as the oxygenate feedstream. Non-limiting examples of a process for producing an oxygenatefeed stream from hydrocarbons and using it to produce olefins isdescribed in EP-B-0 933 345, which is herein fully incorporated byreference.

The feed stream, preferably an oxygenate feed stream, in one embodiment,contains one or more diluents, typically used to reduce theconcentration of the active ingredients in the feed stream, and aregenerally non-reactive to the active ingredients in the feed stream ormolecular sieve catalyst composition. Non-limiting examples of diluentsinclude helium, argon, nitrogen, carbon monoxide, carbon dioxide, water,essentially non-reactive paraffins (especially alkanes such as methane,ethane, and propane), essentially non-reactive aromatic compounds, andmixtures thereof. The most preferred diluents are water and nitrogen,with water being particularly preferred.

The diluent, water, is used either in a liquid or a vapor form, or acombination thereof. The diluent is either added directly to a feedstream entering into a reactor or added directly into the reactor, oradded with a molecular sieve catalyst composition. In one embodiment,the amount of diluent in the feed stream is in the range of from about 1to about 99 mole percent, preferably from about 1 to 80 mole percent,more preferably from about 5 to about 50, and most preferably from about5 to about 25 diluent based on the total number of moles of the activecomponents of the feed stream plus diluent in the feed stream.

In one embodiment, other hydrocarbons are added to the feed stream,preferably oxygenate feed stream, either directly or indirectly, andinclude olefin(s), paraffin(s), aromatic(s) (see for example U.S. Pat.No. 4,677,242, addition of aromatics) or mixtures thereof, preferablypropylene, butene, pentene, and other hydrocarbons having 4 or morecarbon atoms, or mixtures thereof.

The various feed streams, preferably oxygenate feed streams, discussedabove are converted primarily into one or more olefin(s). The olefin(s)or olefin monomer(s) produced from the feed stream typically have from 2to 30 carbon atoms, preferably 2 to 8 carbon atoms, more preferably 2 to6 carbon atoms, still more preferably 2 to 4 carbons atoms, and mostpreferably ethylene an/or propylene.

Non-limiting examples of olefin monomer(s) include ethylene, propylene,butene-1, pentene-1, 4-methyl-pentene-1, hexene-1, octene-1 anddecene-1, preferably ethylene, propylene, butene-1, pentene-1,4-methyl-pentene-1, hexene-1, octene-1 and isomers thereof. Other olefinmonomer(s) include unsaturated monomers, diolefins having 4 to 18 carbonatoms, conjugated or non-conjugated dienes, polyenes, vinyl monomers andcyclic olefins.

In the most preferred embodiment, the feed stream, preferably anoxygenate feed stream, is converted in the presence of a molecular sievecatalyst composition into olefin(s) having 2 to 6 carbons atoms,preferably 2 to 4 carbon atoms. Most preferably, the olefin(s), alone orcombination, are converted from an oxygenate feed stream preferablycontaining an alcohol, and most preferably methanol, to the preferredolefin(s) ethylene propylene and/or butylene often referred to as primeolefin(s).

The most preferred oxygenate-to-olefins process is themethanol-to-olefins process. In a methanol-to-olefin process, a methanolcontaining feed stream is converted to olefins in the presence of amethanol-to-olefins catalyst or catalyst composition. In one embodiment,the methanol-to-olefins catalyst or catalyst composition is molecularsieve catalyst composition.

In one embodiment of the process for conversion of an oxygenate feedstream, the amount of olefin(s) produced based on the total weight ofhydrocarbon produced is greater than 50 weight percent, preferablygreater than 60 weight percent, more preferably greater than 70 weightpercent, and most preferably greater than 75 weight percent.

Increasing the selectivity of preferred hydrocarbon products such asethylene and/or propylene from the conversion of an oxygenate using amolecular sieve catalyst composition is described in U.S. Pat. No.6,137,022 (linear velocity), and PCT WO 00/74848 published Dec. 14, 2000(methanol uptake index of at least 0.13), which are all herein fullyincorporated by reference.

As noted, oxygenate-to-olefin processes use molecular sieve catalysts ormolecular sieve catalyst compositions. The molecular sieve catalystscompositions have molecular sieve and binder and/or matrix material. Themolecular sieve catalysts are prepared according to techniques that areknown to a person of ordinary skill in the art.

Molecular sieves include AEI, AFT, APC, ATN, ATT, ATV, AWW, BIK, CAS,CHA, CHI, DAC, DDR, EDI, ERI, GOO, KFI, LEV, LOV, LTA, MON, PAU, PHI,RHO, ROG, THO, AFO, AEL, EUO, HEU, FER, MEL, MFI, MTW, MTT, TON, EMT,FAU, ANA, BEA, CFI, CLO, DON, GIS, LTL, MER, MOR, MWW and SOD andsubstituted forms thereof; and the large pore molecular sieves.Preferably the molecular sieve is a zeolitic or zeolitic-type molecularsieve. Alternatively, the preferred molecular sieve is analuminophosphate (ALPO) molecular sieves and/or silicoaluminophosphate(SAPO) molecular sieves and substituted, preferably metal substituted,ALPO and/or SAPO molecular sieves including the molecular sieves thatare intergrowth materials having two or more distinct phases ofcrystalline structures within one molecular sieve composition.

Binder materials that are useful alone or in combination include varioustypes of hydrated alumina, silicas, and/or other inorganic oxide sol. Inone embodiment, the binders are alumina sols including include Nalco8676 available from Nalco Chemical Co., Naperville, Ill., and Nyacolavailable from The PQ Corporation, Valley Forge, Pa.

Matrix materials include one or more of: rare earth metals, metal oxidesincluding titania, zirconia, magnesia, thoria, beryllia, quartz, silicaor sols, and mixtures thereof, for example silica-magnesia,silica-zirconia, silica-titania, silica-alumina andsilica-alumina-thoria. In an embodiment, matrix materials are naturalclays such as those from the families of montmorillonite and kaolin.These natural clays include sabbentonites and those kaolins known as,for example, Dixie, McNamee, Georgia and Florida clays. Non-limitingexamples of other matrix materials include: haloysite, kaolinite,dickite, nacrite, or anauxite.

The process for converting a feed stream, especially an oxygenate feedstream in the presence of a molecular sieve catalyst composition iscarried out in a reactor process. In one embodiment, the reactor processis a fixed bed reactor process, a fluidized bed reactor process,preferably a continuous fluidized bed reactor process, and mostpreferably a continuous high velocity fluidized bed reactor process.

The reaction processes can take place in a variety of catalytic reactorssuch as hybrid reactors that have a dense bed or fixed bed zones and/orfast fluidized bed reaction zones coupled together, circulatingfluidized bed reactors, riser reactors, and the like. Suitableconventional reactor types are described in for example U.S. Pat. No.4,076,796, U.S. Pat. No. 6,287,522 (dual riser), and FluidizationEngineering, D. Kunii and O. Levenspiel, Robert E. Krieger PublishingCompany, New York, N.Y. 1977, which are all herein fully incorporated byreference.

The preferred oxygenate-to-olefin reactor is a riser reactor. Riserreactors are generally described in Riser Reactor, Fluidization andFluid-Particle Systems, pages 48 to 59, F. A. Zenz and D. F. Othmer,Reinhold Publishing Corporation, New York, 1960, and U.S. Pat. No.6,166,282 (fast-fluidized bed reactor), and U.S. patent application Ser.No. 09/564,613 filed May 4, 2000 (multiple riser reactor), which are allherein fully incorporated by reference.

In the preferred embodiment, a fluidized bed process or high velocityfluidized bed process includes a reactor, a regenerator, and a recoverysystem.

The reactor or reactor system preferably is a fluid bed reactor systemhaving a first reaction zone within one or more riser reactor(s) and asecond reaction zone within at least one disengaging vessel, preferablycomprising one or more cyclones. In one embodiment, the one or moreriser reactor(s) and disengaging vessel is contained within a singlereactor vessel. Feed stream, preferably an oxygenate feed stream,optionally with one or more diluent(s), is fed to the one or more riserreactor(s) in which a zeolite, zeolite-type molecular sieve catalyst,silicaluminophosphate catalyst composition or coked version thereof isintroduced. In one embodiment, the molecular sieve catalyst compositionor coked version thereof is contacted with a liquid or gas, orcombination thereof, prior to being introduced to the riser reactor(s).Preferably, the liquid is water or methanol, and the gas is an inert gassuch as nitrogen.

In an embodiment, the feed stream, preferably an oxygenate feed stream,is feed into the reactor in the vapor form or the liquid form. The vaporform of the feed stream is referred to as a vapor feed stream. The feedstream in the liquid form is referred to as the liquid feed stream. Theamount of liquid feed stream fed separately or jointly with a vapor feedstream, to a reactor system is in the range of from 0.1 weight percentto about 85 weight percent, preferably from about 1 weight percent toabout 75 weight percent, more preferably from about 1 weight percent toabout 10 weight percent based on the total weight of the feed streamincluding any diluent contained therein. The liquid and vapor feedstreams are preferably of similar composition, or contain varyingproportions of the same or different feed stream compositions withvarying proportions of the same or different diluent compositions.

The feed stream, preferably an oxygenate feed stream, entering thereactor system is preferably converted, partially or fully, in the firstreactor zone into a reactor effluent stream that enters the disengagingvessel along with a coked molecular sieve catalyst composition. In thepreferred embodiment, particle size separators within the disengagingvessel are designed to separate catalyst particles from the reactoreffluent stream containing one or more olefin(s) within the disengagingzone as well as separate catalyst particles from catalyst finesentrained in the reactor effluent stream. Cyclones are preferredparticle size separators. Cyclones generally retain catalyst particlesbut do not retain catalyst fines.

Gravity effects within the disengaging vessel will also separate thecatalyst particles from the reactor effluent stream. Other methods forseparating the catalyst particles from the reactor effluent streaminclude the use of plates, caps, elbows, and the like.

In one embodiment, the reactor effluent stream as it leaves the reactorcomprises ethylene and propylene, C₄+ olefins, methane, C₂+ parafins,water, unreacted oxygenate feed stream, and oxygenate hydrocarbons. Inanother embodiment, the reactor effluent stream comprises from about 30wt. % to about 70 wt. % water, preferably, from about 35 wt. % to about70 wt. % water; more preferably from about 40 wt. % to about 65 wt. %water expressed as a percentage of the total weight of the reactoreffluent stream. According to another aspect of the invention, there arecatalyst fines entrained in the reactor effluent stream. The weight ofcatalyst in the reactor effluent stream, including catalyst fines,expressed as a percent of the weight of the reactor effluent stream plusentrained catalyst comprises about 5 wt. % or less, preferably about 2wt. % or less, more preferably about 1 wt. % or less; even morepreferably about 0.5 wt. % or less. In another embodiment, the weight ofthe catalyst, including catalyst fines, expressed as a percentage of theweight of the reactor effluent stream plus entrained catalyst comprisesfrom about 0.00005 wt. % to about 0.5 wt. %; preferably; from about0.0001 wt. % to about 0.1 wt. %.

In another embodiment, about 10 wt. % or less, preferably about 5 wt. %or less, most preferably about 1 wt. % or less of the catalyst fines inthe reactor effluent stream has a particle size greater than 40 microns,based upon the total weight of catalyst fines in the reactor effluentstream.

In one embodiment of the disengaging system, the disengaging systemincludes a disengaging vessel, typically a lower portion of thedisengaging vessel is a stripping zone. In the stripping zone the cokedmolecular sieve catalyst composition is contacted with a gas, preferablyone or a combination of steam, methane, carbon dioxide, carbon monoxide,hydrogen, or an inert gas such as argon, preferably steam, to recoveradsorbed hydrocarbons from the coked molecular sieve catalystcomposition that is then introduced to the regeneration system. Inanother embodiment, the stripping zone is in a separate vessel from thedisengaging vessel and the gas is passed at a gas hourly superficialvelocity (GHSV) of from 1 hr⁻¹ to about 20,000 hr⁻¹ based on the volumeof gas to volume of coked molecular sieve catalyst composition,preferably at an elevated temperature from about 250° C. to about 750°C., preferably from about 350° C. to 650° C., over the coked molecularsieve catalyst composition.

The conversion temperature employed in the conversion process,specifically within the reactor system, is in the range of from about200° C. to about 1000° C., preferably from about 250° C. to about 800°C., more preferably from about 250° C. to about 750° C., yet morepreferably from about 300° C. to about 650° C., yet even more preferablyfrom about 350° C. to about 600° C., and most preferably from about 350°C. to about 550° C.

The conversion pressure employed in the conversion process, specificallywithin the reactor system, varies over a wide range including autogenouspressure. The conversion pressure is based on the partial pressure ofoxygenate in the oxygenate feed stream exclusive of any diluent therein.Typically, the conversion pressure employed in the process is in therange of from about 0.1 kPaa to about 5 MPaa, preferably from about 5kPaa to about 1 MPaa, and most preferably from about 20 kPaa to about500 kPaa.

The weight hourly space velocity (WHSV), particularly in a process forconverting an oxygenate feed stream in the presence of a molecular sievecatalyst composition within a reaction zone, is defined as the totalweight of the oxygenate feed stream excluding any diluents to thereaction zone per hour per weight of molecular sieve in the molecularsieve catalyst composition in the reaction zone. The WHSV is maintainedat a level sufficient to keep the catalyst composition in a fluidizedstate within a reactor.

Typically, the WHSV ranges from about 1 hr⁻¹ to about 5000 hr⁻¹,preferably from about 2 hr⁻¹ to about 3000 hr⁻¹, more preferably fromabout 5 hr⁻¹ to about 1500 hr⁻¹, and most preferably from about 10 hr⁻¹to about 1000 hr⁻¹. In one preferred embodiment, the WHSV is greaterthan 20 hr⁻¹, preferably the WHSV for conversion of an oxygenate feedstream containing methanol and dimethyl ether is in the range of fromabout 20 hr⁻¹ to about 300 hr⁻¹.

The superficial gas velocity (SGV) of an oxygenate feed stream includingdiluent and reaction products within the reactor system is preferablysufficient to fluidize the molecular sieve catalyst composition within areaction zone in the reactor. The SGV in the process, particularlywithin the reactor system, more particularly within the riserreactor(s), is at least 0.1 meter per second (m/sec), preferably greaterthan 0.5 m/sec, more preferably greater than 1 m/sec, even morepreferably greater than 2 m/sec, yet even more preferably greater than 3m/sec, and most preferably greater than 4 m/sec. See for example U.S.patent application Ser. No. 09/708,753 filed Nov. 8, 2000, which isherein incorporated by reference.

In one preferred embodiment of the process for converting anoxygenate-to-olefin(s) using a silicoaluminophosphate molecular sievecatalyst composition, the process is operated at a WHSV of at least 20hr⁻¹ and a Temperature Corrected Normalized Methane Selectivity (TCNMS)of less than 0.016, preferably less than or equal to 0.01. See, forexample, U.S. Pat. No. 5,952,538 that is herein fully incorporated byreference.

Other processes for converting an oxygenate such as methanol to one ormore olefin(s) using a molecular sieve catalyst composition aredescribed in PCT WO 01/23500 published Apr. 5, 2001 (propane reductionat an average catalyst feedstock exposure of at least 1.0), which isherein incorporated by reference.

The process of converting oxygenates to olefins with certain molecularsieve catalyst compositions causes carbonaceous deposits or “coke” tobuild up on the catalyst. In one embodiment, the cooked molecular sievecatalyst or coked catalyst is withdrawn from a disengaging vessel of thereactor, preferably by one or more cyclones(s). The coked catalyst isintroduced into a regenerator. In the regenerator, the cooked catalystis contacted with a regeneration medium, preferably a gas containingoxygen, under general regeneration conditions of temperature, pressure,and residence time.

Non-limiting examples of the regeneration medium include one or more ofoxygen, O₃, SO₃, N₂O, NO, NO₂, N₂O₅, air, air diluted with nitrogen orcarbon dioxide, oxygen and water (U.S. Pat. No. 6,245,703), carbonmonoxide and/or hydrogen. The regeneration conditions are those capableof burning coke from the coked catalyst composition, preferably to alevel less than 0.5 weight percent based on the total weight of thecoked molecular sieve catalyst composition entering the regenerationsystem. The coked molecular sieve catalyst composition withdrawn fromthe regenerator forms a regenerated molecular sieve catalystcomposition.

The regeneration temperature is in the range of from about 200° C. toabout 1500° C., preferably from about 300° C. to about 1000° C., morepreferably from about 450° C. to about 750° C., and most preferably fromabout 550° C. to 700° C. The regeneration pressure is in the range offrom about 15 psia (103 kPaa) to about 500 psia (3448 kPaa), preferablyfrom about 20 psia (138 kPaa) to about 250 psia (1724 kPaa), morepreferably from about 25 psia (172 kPaa) to about 150 psia (1034 kPaa),and most preferably from about 30 psia (207 kPaa) to about 60 psia (414kPaa).

The preferred residence time of a catalyst, including a molecular sievecatalyst, in the regenerator is in the range of from about one minute toseveral hours, most preferably about one minute to about 100 minutes. Inone embodiment, the preferred volume of oxygen in the gas is in therange of from about 0.01 mole percent to about 5 mole percent based onthe total volume of the gas.

In one embodiment, regeneration promoters, typically metal containingcompounds such as platinum, palladium and the like, are added to theregenerator directly, or indirectly, for example with coked catalyst.Also, in another embodiment, fresh molecular sieve catalyst is added tothe regenerator containing a regeneration medium of oxygen and water asdescribed in U.S. Pat. No. 6,245,703, which is herein fully incorporatedby reference.

According to one embodiment, the burning of catalyst including catalystparticles in the regenerator produces a flue gas and regeneratedcatalyst, including regenerated catalyst particles and regeneratedcatalyst fines. The flue gas is defined as the gaseous output of theregenerator. The flue gas is separated from the regenerated catalystparticles by a particle size separator such as a cyclonic separator orcyclone. The cyclones retain catalyst particles but allow the flue gasto exit the regenerator. Additionally, regenerated catalyst fines arecarried in the flue gas and leave the regenerator.

The burning of coke is an exothermic reaction, and in an embodiment, thetemperature within the regeneration system is controlled by varioustechniques in the art including feeding a cooled gas to the regeneratorvessel, operated either in a batch, continuous, or semi-continuous mode,or a combination thereof. A preferred technique involves withdrawing theregenerated catalyst from the regeneration system and passing theregenerated catalyst through a catalyst cooler that forms a cooledregenerated catalyst. The catalyst cooler, in an embodiment, is a heatexchanger that is located either internal or external to theregeneration system.

In one embodiment, the cooler regenerated catalyst is returned to theregenerator in a continuous cycle, alternatively, (see U.S. patentapplication Ser. No. 09/587,766 filed Jun. 6, 2000) a portion of thecooled regenerated catalyst is returned to the regenerator vessel in acontinuous cycle, and another portion of the cooled regenerated catalystis returned to the riser reactor(s), directly or indirectly, or aportion of the regenerated catalyst or cooled regenerated catalyst iscontacted with by-products within the reactor effluent stream (PCT WO00/49106 published Aug. 24, 2000), which are all herein fullyincorporated by reference. In another embodiment, a regenerated catalystcontacted with an alcohol, preferably ethanol, 1-propanol, 1-butanol ormixture thereof, is introduced to the reactor system, as described inU.S. patent application Ser. No. 09/785,122 filed Feb. 16, 2001, whichis herein fully incorporated by reference.

Other methods for operating a regeneration system are in disclosed U.S.Pat. No. 6,290,916 (controlling moisture), which is herein fullyincorporated by reference.

The regenerated catalyst particles are withdrawn from the regeneratorand returned to the reactor. In one embodiment, the regenerated catalystparticles that are withdrawn from the regeneration system, preferablyfrom the catalyst cooler, are combined with a fresh catalyst and/orre-circulated catalyst and/or feed stream and/or fresh gas or liquids,and returned to the riser reactor(s). In another embodiment, theregenerated catalyst withdrawn from the regeneration system is returnedto the riser reactor(s) directly, optionally after passing through acatalyst cooler. In one embodiment, a carrier, such as an inert gas,vapor feed stream, steam or the like, semi-continuously or continuously,facilitates the introduction of the regenerated catalyst to the reactoror reactor system, preferably to the one or more riser reactor(s).

In one embodiment, the optimum level of coke on the catalyst compositionin the reaction zone is maintained by controlling the flow of theregenerated catalyst or cooled regenerated catalyst from theregeneration system to the reactor system. There are many techniques forcontrolling the flow of a catalyst described in Michael Louge,Experimental Techniques, Circulating Fluidized Beds, Grace, Avidan andKnowlton, eds., Blackie, 1997 (336-337), which is herein incorporated byreference. This is referred to as the complete regeneration mode. Inanother embodiment, the optimum level of coke on the molecular sievecatalyst in the reaction zone is maintained by controlling the flow rateof the oxygen-containing gas flow to the regenerator. This is referredto as the partial regeneration mode.

Coke levels, or the level of carbonaceous deposits on the catalyst, aremeasured by withdrawing from the conversion process the catalystcomposition at a point in the process and determining its carboncontent.

In one preferred embodiment, the catalyst in the reaction zone containsin the range of from about 1 to 50 weight percent, preferably from about2 to 30 weight percent, more preferably from about 2 to about 20 weightpercent, and most preferably from about 2 to about 10 coke orcarbonaceous deposit based on the total weight of the mixture ofcatalyst. See for example U.S. Pat. No. 6,023,005, which is herein fullyincorporated by reference. It is recognized that the catalyst in thereaction zone is made up of a mixture of regenerated catalyst andcatalyst that has ranging levels of carbonaceous deposits. The measuredlevel of carbonaceous deposits thus represents an average of the levelsan individual catalyst particle.

As noted above, the reactor effluent stream leaves the reactor throughparticle size separators. The reactor effluent stream optionally passesthrough a heat exchanger system. According to one embodiment the heatexchanger system comprises one or more heat exchangers, preferably twoto four heat exchangers, most preferably two or three heat exchangers.Optionally, the heat exchanger system cools the reactor effluent streamto produce a cooled effluent stream. The cooled effluent stream iswithdrawn from the heat exchanger system and is sent to a quench device.

Reactor Effluent Quenching

The oxygenate-to-olefin process forms a substantial amount of water as abyproduct. Furthermore, a substantial amount of catalysts are carried inthe reactor effluent stream. Water and catalyst fines can be removedfrom the reactor effluent stream by a quench device. A “quench device”is a device for removing a portion of the reactor effluent stream byestablishing a sufficient quantity of a liquid phase in contact with thereactor effluent stream which condenses at least a portion of thematerial in the reactor effluent stream. One example of a quench devicein an oxygenate-to-olefin product stream is found in U.S. Pat. No.6,121,504 (direct product quench). The liquid matter that contacts thereactor effluent stream and causes the condensation is called a “quenchmedium.”

In a quench device, at least a portion of the reactor effluent stream israpidly condensed through contact with a quench medium in the liquidstate (a form of what is typically called “direct contact heattransfer”). When quenching in a quench device, at least a portion of thereactor effluent stream remains in a gaseous state. A portion of thereactor effluent stream condenses to form a liquid fraction which iswithdrawn from the quench device as a first liquid stream in oneembodiment. The portion of the reactor effluent stream in a gaseousstate is separated from the liquid fraction.

The portion of the reactor effluent stream that is gaseous underquenching conditions typically comprises prime olefins, dimethyl ether,methane, CO, CO₂, ethane, propane, and any water and unreacted oxygenatefeed stream that is not condensed during the operation of the quenchdevice. These gaseous compounds in the reactor effluent stream generallypass through the quench device and form the quenched effluent stream.The quenched effluent stream is defined as the effluent stream after atleast one stage of quenching. The compounds in the reactor effluentstream that are liquid under quenching conditions typically compriseswater, a portion of the unreacted oxygenate feed stream (typicallymethanol), and a small portion of the oxygenate conversion byproducts,e.g. heavy hydrocarbons (C₅+). These compounds form a quench bottomsstream or a liquid fraction. Additionally, quench medium contacts thecatalyst fines in the reactor effluent stream and washes the catalystfines into the liquid fraction. Thus, the liquid fraction containscatalyst fines.

According to one embodiment of the present invention, a quench tower isemployed as a quench device. According to one embodiment the quenchdevice has one or more stages, preferably one to four stages, mostpreferably one to three stages. A one stage quench is disclosed in U.S.Pat. No. 6,121,504, the content of which is incorporated fully byreference. A two stage quench is disclosed in U.S. Pat. No. 6,403,854,the content of which is incorporated fully by reference.

In a particular embodiment, the quench medium is water. In anotherembodiment, the quench medium is a portion of the water that has beenrecovered from the quench device and cooled (thus reintroduced to thequench tower), and which contains at least a portion of the catalystfines separated from the gaseous portion of the reactor effluent streamand is referred to as recovered quench medium. According to oneembodiment, the quench is operated under conditions such that the cooledprocess gas then enters the quench device where effluent water iscondensed, acetic acid is neutralized and some heavy oxygenates(C₃-C₄+aldehydes, ketones & alcohols) are rejected.

As previously described the reactor effluent stream is quenched toremove catalyst fines and water that are present in the reactor effluentstream and produces a quenched effluent stream.

In an embodiment of the invention, the quenched effluent stream containsboth ethylene and propylene. Desirably, the quenched effluent streamcontains about 50 wt. % or more, preferably from about 50 wt. % to about95 wt. %, more preferably from about 55 wt. % to about 90 wt. %, andmost preferably from about 60 wt. % to about 85 wt. % ethylene andpropylene based upon the total weight of the quenched effluent stream asit leaves the quench device.

In another embodiment, the quenched effluent stream comprises about 25wt. % or more from about 25 wt. % ethylene to about 75 wt. %, morepreferably from about 30 wt. % to about 60 wt. %, and most preferablyfrom about 35 wt. % to about 50 wt. % ethylene based upon the totalweight of the quenched effluent stream after it leaves the quenchdevice.

In another embodiment, the quenched effluent stream comprises about 20wt. % or more, preferably from about 20 wt. % to about 70 wt. %, morepreferably from about 25 wt. % to about 50 wt. %, and most preferablyfrom about 30 wt. % to about 40 wt. % propylene based upon the totalweight of the quenched effluent stream after it leaves the quenchdevice.

It is desirable that the quenched effluent stream contains a relativelylow concentration of ethane, preferably a lower concentration of ethanethan propane. Preferably, the quenched effluent stream comprises about 4wt. % or less, more preferably about 3 wt. % or less, and mostpreferably about 2 wt. % or less ethane based upon the total weight ofthe quenched effluent stream after it leaves the quench device.

It is also desirable that the quenched effluent stream contains arelatively low concentration of propane. Preferably, the quenchedeffluent stream comprises about 5 wt. % or less, more preferably about 4wt. % or less, and most preferably about 3 wt. % or less propane basedupon the total weight to the quenched effluent stream after it leavesthe quench device.

In one embodiment, the quenched effluent stream that is providedcomprises about 50 wt. % or less, preferably about 20 wt. % or less,more preferably about 10 wt. % or less, and most preferably about 5 wt.% or less dimethyl ether. In an embodiment, the provided olefins streamwill contain at about 100 wppm or more, preferably about 500 wppmdimethyl ether or more, and more preferably about 1,000 wppm or moredimethyl ether based upon the total weight of the quenched effluentstream as it leaves the quench device.

In another embodiment of the invention, the quenched effluent stream isfurther processed by compression, preferably multi-staged compression.Two, three, four or more stages can be used, with two or three stagesbeing preferred.

Desirably, the quenched effluent stream is compressed to a pressure thatis greater than that at which the oxygenate-to-olefin reaction processis carried out. Preferably, the quenched effluent stream is compressedto a pressure of about 30 psia (207 kPa) or more, more preferably about50 psia (345 kPa) or more, most preferably about 100 psia (689 kPa) ormore. High-pressure ranges are particularly preferred, with the upperlimit being a practical one based on cost of design and ease ofoperation. In an embodiment, the pressure is from about 1,000 psia(6,895 kPa) to about 5,000 psia (34,450 kPa), preferably from about 750psia (5171 kPa) to about 5,000 psia (34,450 kPa), more preferably fromabout 500 psia (3447 kPa) to about 5,000 psia (34,450 kPa).

Following compression, the quenched effluent stream is further processedby washing to remove acid gases and alternatively other oxygenates anddrying to remove water as described below.

Washing and Drying

An acid gas wash optionally is used to remove acid gas from the quenchedeffluent stream in the first fraction by contacting the first fractionwith an acid gas absorbent or adsorbent. Non-limiting examples of suchabsorbents or adsorbents include amines, potassium carbonate, caustic,alumina, molecular sieves, and membranes, particularly membranes formedof polysulfone, polyimid, polyamide, glassy polymer and celluloseacetate. Solutions containing amines and caustic compounds arepreferred, with caustic compounds being more preferred.

Aqueous amine solutions, which are useful in one embodiment thisinvention, contain any amine compound or compounds suitable for acid gasabsorption. Non-limiting examples include alkanolamines, such astriethanolamine (TEA); methyldiethanolamine (MDEA); diethanolamine(DEA); monoethanolamine (MEA); diisopropanolamine (DIPA); andhydroxyaminoethyl ether (DGA). Effective concentrations range from about0.5 to about 8 moles of amine per liter of aqueous solution in oneembodiment.

Piperazine and/or monomethylethanolamine (MMEA) in one embodiment areadded to aqueous amine solutions to enhance their absorptioncapabilities. These additives are included in the aqueous solution at aconcentration of from about 0.04 to about 2 moles per liter of aqueoussolution.

Caustic compounds, which are used in one embodiment of this invention,are alkaline compounds, which are effective in removing acid gas from anolefin containing stream. Non-limiting examples of such alkalinecompounds include sodium hydroxide and potassium hydroxide.

Following acid gas treating, it is desirable to remove additionallyentrained material in the quenched effluent stream using a water wash.Conventional equipment is optionally used. It is desirable, however, tofurther remove additional water from the quenched effluent streams.

This invention further includes an optional drying embodiment. In thisembodiment, a solid or liquid drying system is used to remove waterand/or additional oxygenated hydrocarbon from the quenched effluentstream.

In the solid drying system, the quenched effluent stream having beenoptionally acid gas treated and water washed, is contacted with a solidadsorbent to further remove water and oxygenated hydrocarbon to very lowlevels. Typically, the adsorption process is carried out in one or morefixed beds containing a suitable solid adsorbent.

Adsorption is useful for removing water and oxygenated hydrocarbons tovery low concentrations, and for removing oxygenated hydrocarbons thatare not normally be removed by using other treatment systems.Preferably, an adsorbent system used as part of this invention hasmultiple adsorbent beds. Multiple beds allow for continuous separationwithout the need for shutting down the process to regenerate the solidadsorbent. For example, in a three bed system typically one bed ison-line, one bed is regenerated off-line, and a third bed is onstand-by.

The specific adsorbent solid or solids used in the adsorbent bedsdepends on the types of contaminants being removed. Non-limitingexamples of solid adsorbents for removing water and various polarorganic compounds, such as oxygenated hydrocarbons and absorbentliquids, include aluminas, silica, 3A molecular sieves, 4A molecularsieves, and alumino-silicates. Beds containing mixtures of these sievesor multiple beds having different adsorbent solids optionally is used toremove water, as well as a variety of oxygenated hydrocarbons.

In one embodiment of this invention, one or more adsorption beds isarranged in series or parallel. In one example of a series arrangement,a first bed is used to remove the smallest and most polar molecules,which are the easiest to remove. Subsequent beds for removing largerless polar oxygenated species are next in series. As a specific exampleof one type of arrangement, water is first selectively removed using a3A molecular sieve. This bed is then followed by one or more bedscontaining one or more less selective adsorbents such as a larger poremolecular sieve e.g. 13X and/or a high surface area active alumina suchas Selexorb CD (Alcoa tradename).

In another embodiment, the first bed is a 3.6A molecular sieve capableof selectively removing both water and methanol. This bed is thenfollowed by one or more 13X or active alumina beds as described above.

The adsorbent beds typically are operated at ambient temperature or atelevated temperature as required, and with either upward or downwardflow. Regeneration of the adsorbent materials are often carried out byconventional methods including treatment with a stream of a dry inertgas such as nitrogen at elevated temperature.

In the liquid drying system, a water absorbent is used to remove waterfrom the quenched effluent stream. The water absorbent of one embodimentis any liquid effective in removing water from an olefin containingstream. Preferably, the water absorbent is a polyol or an alcohol, suchas ethanol or methanol.

Preferably the olefin from the adsorption beds contains less than about100 wppm water, more preferably less than about 10 wppm, and mostpreferably less than 1 wppm. Preferably less than about 10 wppm dimethylether is present in the stream leaving the adsorption beds, morepreferably less than about 5 wppm, and most preferably less than about 1wppm. The step of acid washing and drying produces an olefin stream.

Olefin Product Recovery

The olefin stream from the dryer is further processed to isolate andpurify components in the washed effluent stream, particularly, olefinproduct streams containing prime olefins (i.e. ethylene, propylene, andbutylene). There are many well-known recovery systems, techniques andsequences that are useful in separating and purifying an olefin streaminto one or more olefin product streams, preferably, high purity olefinproduct streams.

As noted the object of one embodiment of the present invention is toisolate prime olefin product streams that contains a C_(x) olefin,wherein x is an integer from 2 to 4, in an amount that is about 80 wt. %or more, preferably about 90 wt. % or more, more preferably about 95 wt.% or more based upon the total weight of the high purity prime olefinstream. It is most preferable to isolate high purity prime olefinstreams that contain C_(x) olefin, wherein x is an integer from 2 to 4,in an amount greater than about 99 wt. % or more, based on the totalweight of the high purity olefin stream. The olefin product stream has apurity grade that is selected for the particular application or end useof the olefin product stream. To accomplish the isolation of primeolefin streams, and preferably high purity prime olefin streams, afractionation train is provided. The fractionation train comprises ademethanizer, a C₂ splitter, a deethanizer, a C₃ splitter, adepropanizer, a debutanizer, and a debutyleneizer. A demethanizer is afractionation tower that separates methane and compounds with a boilingpoint lower than methane from ethylene and compounds with boiling pointhigher than ethylene. A C₂ splitter is a fractionation tower thatseparates ethylene and compounds with a boiling point lower thanethylene from ethane and compounds with boiling point higher thanethane. A deethanizer is a fractionation tower that separates ethane andcompounds with a boiling point lower than ethane from propylene, andcompounds with boiling point higher than propylene. A C₃ splitter is afractionation tower that separates propylene and compounds with aboiling point lower than propylene from propane and compounds withboiling point higher than propane.

A depropanizer is a fractionation tower that separates propane andcompounds with a boiling point lower than propane from butylene andcompounds with boiling point higher than butylene. A debutyleneizer is afractionation tower that separates butylene and compounds with a boilingpoint lower than butane from butane and compounds with boiling pointhigher than butane.

As noted, the dried olefin stream contains other byproducts. Thebyproducts, in one embodiment, need to be removed from the final olefinproduct streams. Alkynes and dienes are byproducts of theoxygenate-to-olefin reaction and are typically not found, in significantamounts, in the final olefin product streams.

Hydrogenation is a way of eliminating alkynes and/or dienes from theolefin product stream. Hydrogenation reacts an unsaturated hydrocarbon,such as an alkyne and/or diene with hydrogen to hydrogenate. Preferably,in the case of hydrogenation of an alkyne, the triple bond in the alkyneis saturated by adding one hydrogen molecule across the triple bondresulting in a double bond—i.e. an olefin. In the case a diene, one ofthe two double bonds is saturated by adding one hydrogen molecule acrossone of the double bonds resulting in one double bond—i.e. an olefin.Hydrogenation units include without limitation acetylene converters andmethyl acetylene and/or propadiene converters. There are types ofacetylene converters distinguished by their location relative to ademethanizer. Front-end acetylene converters are located before thedemethanizer. Back-end acetylene converters, are located after thedemethanizer. Front-end acetylene converters convert acetylene in thepresence of indigenous hydrogen. Indigenous hydrogen is hydrogen that isproduced as a byproduct of the oxygenate-to-olefin reaction and was notremoved from the olefin stream. Back-end acetylene converters convertacetylene to ethylene after the demethanizer. The demethanizer separatesany indigenous hydrogen that was produced as a byproduct from theoxygenate-to-olefin reaction from the ethylene and higher boiling pointcompounds. Thus, in a back end acetylene converter a hydrogen sourcemust be added to the olefin stream before hydrogenation of the alkynesand/or dienes. The hydrogen source, in one embodiment, is in whole, orin part, separated from the olefin stream. The hydrogen source stream,of one embodiment comprises in whole, or in part, hydrogen produced fromthe oxygenate-to-olefin reaction. The hydrogen source in anotherembodiment is produced from decomposition of methanol and/or otheroxygenates optionally followed by shifting the carbon monoxide producedfrom oxygenate decomposition to hydrogen by reaction with water.

The olefin stream, for the purpose of this invention is the feed streamto the hydrogenation unit. The olefin stream in one embodiment is anethylene stream. In another embodiment, the olefin stream is a propylenestream. In still another embodiment, the olefin stream is a butylenestream. In one embodiment, the olefin stream is a first olefin streamand contains any combination of ethylene, propylene and/or butylene. Inone embodiment, the first olefin stream contains about 50 mol. % ormore, preferably about 90 mol. % or more, more preferably about 98 mol.% or more, most preferably about 95 mol. % or more olefin based upon thecomposition of the first olefin stream. In one embodiment, the firstolefin stream comprises about 25 mol. % or more, preferably about 90mol. % or more, most preferably about 98 mol. % or more ethylene basedupon the composition of the first olefin stream. In another embodiment,the first olefin stream comprises about 25 mol. % or more, preferablyabout 90 mol. % or more, most preferably about 95 mol. % or morepropylene based upon the composition of the first olefin stream.

In still another embodiment, there are about 500 mppm or less, typicallyabout 200 mppm, more typically about 50 mppm or less alkynes and/ordienes in the first olefin stream based upon the composition of thefirst olefin stream. In still another embodiment, the alkynes and/ordienes are acetylene and the first olefin stream comprises about 500mppm or less, typically about 200 mppm, more typically about 50 mppm orless acetylene based upon the composition of the first olefin stream. Inanother embodiment, the alkynes and/or dienes are methyl acetyleneand/or propadiene and the first olefin stream comprises about 500 mppmor less, typically about 200 mppm, more typically about 50 mppm or lessmethyl acetylene and/or propadiene based upon the composition of thefirst olefin stream.

As noted, the first olefin stream of one embodiment, comprisesindigenous hydrogen. In one embodiment, the first olefin streamcomprises indigenous hydrogen in an amount ranging from about 0.1 mol. %to about 1.0 mol. %, preferably from about 0.2 mol. % to about 0.6 mol.% indigenous hydrogen based upon the composition of the first olefinstream.

In another embodiment, hydrogen is added to the first olefin stream asshown in FIG. 2. Hydrogen source stream flows along line 26 and iscombined with the first olefin stream flowing along line 20. In oneembodiment, the hydrogen source stream is from a source selected fromthe group comprising pipeline hydrogen, hydrogen from reformed naphtha,hydrogen from refinery streams, hydrogen from bottled sources, hydrogenfrom water electrolysis reactors, hydrogen from refinery streams,hydrogen from methanol decomposition and hydrogen from theoxygenate-to-olefin process that was removed from the olefin stream. Inyet another embodiment, the added hydrogen is from a hydrogen sourcestream having about 90 mol. % or more, preferably from about 95 mol. %or more, more preferably about 98 mol. % or more, most preferably about99 mol. % or more hydrogen based upon the composition of the hydrogensource stream.

In an embodiment, the hydrogen source stream and the olefin streamcombine to form a combined stream that flows along line 27. In oneembodiment, the combined stream or the first olefin stream has about 500mppm or less, preferably about 400 mppm or less, more preferably about300 mppm or less methane based upon the composition of the respectivecombined stream or first olefin stream. In one embodiment, the combinedstream or the first olefin stream has about 500 mppm or less, preferablyabout 400 mppm, more preferably about 300 mppm or less methane andnitrogen based upon the composition of the respective combined stream orthe first olefin stream. In another embodiment, the combined stream orthe first olefin stream has about 1 mppm or less CO based upon thecomposition of the respective combined stream or first olefin stream. Instill another embodiment, the combined stream, the first olefin streamor the hydrogen source stream has about 1 mppm or less CO₂ based uponthe composition of the respective combined stream, first olefin streamor hydrogen source stream.

According to one embodiment, excess hydrogen from the hydrogen sourcestream is added to the first olefin stream. Particularly, about 1.05moles or more of hydrogen, preferably from about 1.5 moles to about 50moles of hydrogen, more preferably from about 1.5 moles to about 10moles of hydrogen is added for every mole of alkynes and/or dienes inthe first olefin stream.

According to an embodiment, the first olefin stream and/or the combinedstream is heated, preferably with the third olefin stream in a heatexchanger. The first olefin stream travels along line 20 and passesthrough a first heat exchanger 22 and a second heat exchanger 24. Thefirst heat exchanger 22 and/or second heat exchanger 24 heat the firstolefin stream to a desired temperature. Optionally and alternatively,the first heat exchanger 22 and/or second heat exchanger are located online 27 and heat the combined olefin stream. According to oneembodiment, the first olefin stream and/or the combined olefin streamare heated to a temperature ranging from about 100° F. (38° C.) to about250° F. (121° C.), preferably from about 120° F. (49° C.) to about 200°F. (93° C.), more preferably from about 150° F. (66° C.) to about 190°F. (88° C.).

As noted the first olefin stream and/or combined olefin stream arehydrogenated in a first hydrogenation step. The hydrogenation stepconverts alkynes and/or dienes, such as acetylene, methyl acetylene,and/or propadiene to olefins. A competing reaction occurs that convertsolefins to paraffins. Thus, it is desirable in one embodiment that theconditions for the reaction favor the reaction of converting alkynesand/or dienes to olefins rather than converting the olefins toparaffins. If the latter reaction is favored, an unacceptable level ofalkynes and/or dienes is likely to remain in the olefin stream after thefirst hydrogenation step. This is due particularly to the high amount ofolefin product by volume relative to amount of olefin by volume in thefirst olefin stream and/or combined olefin stream.

According to one embodiment, the catalyst that is used in the firsthydrogenation step (“first catalyst”) is selected from the groupconsisting of Group VIII metal hydrogenation catalysts. See U.S. Pat.Nos. 3,679,762, 4,571,442, 4,347,392, 4,128,595, 5,059,732, and4,762,956 for examples of hydrogenation reactors and hydrogenationcatalyst—all of these references are fully incorporated by referenceinto the present application. Preferably the first catalyst is anelemental Group VIII metal catalysts or combinations thereof. Byelemental it is meant a catalyst that contains the identified elementwhether in its pure form or in the form of a salt. More preferably, thefirst catalyst is an elemental noble metal catalyst on a silica and/oralumina substrate with a co-catalyst selected from the group consistingof elemental silver, vanadium or iodine or combinations thereof.

According to one embodiment, the first hydrogenation step occurs at apressure ranging from about 50 psia (344 kPaa) to about 400 psia (2760kPaa), preferably from about 200 psia (1380 kPaa) to about 300 psia(2070 kPaa), and more preferably from about 250 psia (1720 kPaa) toabout 300 psia (2070 kPaa). With reference to FIG. 2, the combinedolefin stream of one embodiment is transported along line 27 into afirst reactor 28. The first reactor 28 contains a first catalyst. Itproduces a second olefin stream that is withdrawn from the first reactor28 along line 30. The second olefin stream is defined as the olefinstream after one hydrogenation step. The second olefin stream comprisesabout 10 mppm or less, preferably about 5 mppm or less, more preferablyabout 2 mppm or less alkyne based upon the composition of the secondolefin stream. In one embodiment, the alkyne is acetylene. In anotherembodiment, the alkyne is methyl acetylene and/or propadiene.

In another embodiment, the amount of hydrogen in the second olefinstream is from about 100 mppm to about 1000 mppm, preferably from about50 mppm to about 250 mppm, most preferably from about 10 mppm to about100 mppm based upon the weight of the second olefin stream.

As shown in FIG. 2, the second olefin stream travels along line 30 to athird (and optional) heat exchanger 32. The third heat exchanger 32 iscapable of heating or cooling the second olefin stream as needed toadjust the temperature of the second olefin stream before a secondhydrogenation step. According to an embodiment, the temperature of thesecond olefin stream ranges from about 100° F. (38° C.) to about 250° F.(121° C.), preferably from about 120° F. (49° C.) to about 200° F. (93°C.), more preferably from about 150° F. (66° C.) to about 190° F. (88°C.) before the second hydrogenation step.

According to another embodiment, second hydrogenation step occurs at apressure ranging from about 50 psia (344 kPaa) to about 400 psia (2760kPaa), preferably from about 200 psia (1380 kPaa) to about 300 psia(2070 kPaa), and more preferably from about 250 psia (1720 kPaa) toabout 300 psia (2070 kPaa).

According to one embodiment, the catalyst in the second hydrogenationstep (“second catalyst”) is an elemental Group VIII metal catalysts orcombinations thereof. By elemental it is meant a catalyst that containsthe identified element whether in its pure form or in the form of asalt. More preferably, the second catalyst is an elemental noble metalcatalyst on a silica and/or alumina substrate with a co-catalystconsisting of elemental nickel and/or iron. In one embodiment, thesecond catalyst is the same as the first catalyst. With continuedreference to FIG. 2, the second olefin stream passes along line 30 intothe second hydrogenation reactor 34 for a second hydrogenation step. Thepurpose of the second hydrogenation step, according to one embodiment,is to chemically react all remaining hydrogen so that below acceptablelevels of hydrogen remains after the second hydrogenation step. Thesecond hydrogenation step is typically. non-selective so that theremaining hydrogen reacts with olefin as well as alkynes and dienes. Thesecond hydrogenation reactor 34 contains the second hydrogenationcatalyst.

In an alternative embodiment, the second hydrogenation step occurs inthe same reaction vessel as the first hydrogenation step. In such anembodiment, not illustrated in FIG. 2 a reactor has a firsthydrogenation bed comprising a first hydrogenation catalyst and a secondhydrogenation bed containing a second hydrogenation catalyst.

The second hydrogenation step produces a third olefin stream orhydrogenated olefin stream.

The third olefin stream is defined as the olefin stream after two stepsof hydrogenation and is withdrawn along line 36. The third olefin streamcomprises olefins such as prime olefins (i.e. ethylene, propylene,and/or butylene). In one embodiment, the amount of hydrogen in the thirdolefin stream is about 20 mppm or less, preferably about 10 mppm orless, more preferably about 5 mppm or less, most preferably about 1 mppmor less, based upon the composition of the third olefin stream.According to one embodiment, the amount of alkynes and/or dienes isabout 5 mppm or less, preferably about 1 mppm or less, more preferablyabout 0.5 mppm or less. According to one embodiment, about 1 mol. % orless, more preferably about 500 mppm or less, even more preferably about200 mppm or less and most preferably about 100 mppm or less of theolefins are hydrogenated in the first and second step based upon thecomposition of the first olefin stream. According to one embodiment,about 1 mol. % or less, more preferably about 500 mppm or less, evenmore preferably about 200 mppm or less and most preferably about 100mppm or less ethylene are hydrogenated in the first and second stepbased upon the composition of the first olefin stream. According to oneembodiment, about 1 mol. % or less, more preferably about 500 mppm orless, even more preferably about 200 mppm or less and most preferablyabout 100 mppm or less propylene are hydrogenated in the first andsecond step based upon the composition of the first olefin stream.According to one embodiment, a single step of reacting reacts topreferentially eliminate all alkynes and/or dienes over olefins andchemically reacts all remaining hydrogen and conditions described abovefor the first reaction step and/or the second reaction step.

According to an embodiment referenced in FIG. 2, the third olefin streamleaves the second reactor along line 36 and passes through the firstheat exchanger 22 where the third olefin stream is optionally cooled bythe first olefin stream. In another step, the olefin stream passesthrough a fourth (and optional) heat exchanger 38 referred to as afourth heat exchanger 38. The fourth heat exchanger 38 further cools theolefin stream. According to one embodiment, the cooling step iscryogenic. Thereafter, the third olefin stream continues to afractionation step to further fractionate the olefin stream into productstreams according to established principles of olefin fractionation.

Olefin Product Use

Suitable well-known reaction systems that follow the recovery systemprimarily take lower value products and convert them to higher valueproducts. For example, the C₄ hydrocarbons, butene-1 and butene-2 areused to make alcohols having 8 to 13 carbon atoms, and other specialtychemicals, isobutylene is used to make a gasoline additive,methyl-t-butylether, butadiene in a selective hydrogenation unit isconverted into butene-1 and butene-2, and butane is useful as a fuel.

Non-limiting examples of reaction systems that take lower value productsand convert them to higher value products include U.S. Pat. No.5,955,640 (converting a four carbon product into butene-1), U.S. Pat.No. 4,774,375 (isobutane and butene-2 alkylated to an alkylategasoline), U.S. Pat. No. 6,049,017 (dimerization of n-butylene), U.S.Pat. Nos. 4,287,369 and 5,763,678 (carbonylation or hydroformulation ofhigher olefins with carbon dioxide and hydrogen making carbonylcompounds), U.S. Pat. No. 4,542,252 (multistage adiabatic process), U.S.Pat. No. 5,634,354 (olefin-hydrogen recovery), and Cosyns, J. et al.,Process for Upgrading C₃, C₄ and C₅ Olefinic Streams, Pet. & Coal, Vol.37, No. 4 (1995) (dimerizing or oligomerizing propylene, butylene andpentylene), which are all herein fully incorporated by reference.

Other uses for one or more olefin products are disclosed in U.S. Pat.No. 6,121,503 (making plastic with an olefin product having a paraffinto olefin weight ratio less than or equal to 0.05), U.S. Pat. No.6,187,983 (electromagnetic energy to reaction system), PCT WO 99/18055publishes Apr. 15, 1999 (heavy hydrocarbon in effluent stream fed toanother reactor) PCT WO 01/60770 published Aug. 23, 2001 and U.S. patentapplication Ser. No. 09/627,634 filed Jul. 28, 2000 (high-pressure),U.S. patent application Ser. No. 09/507,838 filed Feb. 22, 2000 (stagedfeedstock injection), and U.S. patent application Ser. No. 09/785,409filed Feb. 16, 2001 (acetone co-fed), which are all herein fullyincorporated by reference.

In another embodiment, olefin(s) produced are directed to, in oneembodiment, one or more polymerization processes for producing variouspolyolefins. (See for example U.S. patent application Ser. No.09/615,376 filed Jul. 13, 2000 that is herein fully incorporated byreference.)

Polymerization processes include solution, gas phase, slurry phase and ahigh-pressure process, or a combination thereof. Particularly preferredis a gas phase or a slurry phase polymerization of one or more olefin(s)at least one of which is ethylene or propylene. Polymerization processesinclude those non-limiting examples described in the following: U.S.Pat. Nos. 4,543,399, 4,588,790, 5,028,670, 5,317,036, 5,352,749,5,405,922, 5,436,304, 5,453,471, 5,462,999, 5,616,661, 5,627,242,5,665,818, 5,677,375, 5,668,228, 5,712,352 and 5,763,543 and EP-A-0 794200, EP-A-0 802 202, EP-A2-0 891 990 and EP-B-0 634 421 describe gasphase polymerization processes; U.S. Pat. Nos. 3,248,179 and 4,613,484,6,204,344, 6,239,235 and 6,281,300 describe slurry phase polymerizationprocesses; U.S. Pat. Nos. 4,271,060, 5,001,205, 5,236,998 and 5,589,555describe solution phase polymerization processes; and U.S. Pat. Nos.3,917,577, 4,175,169, 4,935,397, and 6,127,497 describe high-pressurepolymerization processes; all of which are herein fully incorporated byreference.

These polymerization processes utilize a polymerization catalyst thatoptionally includes any one or a combination of the molecular sievecatalysts discussed above. However, the preferred polymerizationcatalysts are those Ziegler-Natta, Phillips-type, metallocene,metallocene-type and advanced polymerization catalysts, and mixturesthereof. Non-limiting examples of polymerization catalysts are describedin U.S. Pat. Nos. 3,258,455, 3,305,538, 3,364,190, 3,645,992, 4,076,698,4,115,639, 4,077,904 4,482,687, 4,564,605, 4,659,685, 4,721,763,4,879,359, 4,960,741, 4,302,565, 4,302,566, 4,302,565, 4,302,566,4,124,532, 4,302,565, 5,763,723, 4,871,705, 5,120,867, 5,324,800,5,347,025, 5,384,299, 5,391,790, 5,408,017, 5,491,207, 5,455,366,5,534,473, 5,539,124, 5,554,775, 5,621,126, 5,684,098, 5,693,730,5,698,634, 5,710,297, 5,714,427, 5,728,641, 5,728,839, 5,753,577,5,767,209, 5,770,753 and 5,770,664, 5,527,752, 5,747,406, 5,851,945 and5,852,146, all of which are herein fully incorporated by reference.

In preferred embodiment, the present invention comprises a polymerizingprocess of one or more olefin(s) in the presence of a polymerizationcatalyst system in a polymerization reactor to produce one or morepolymer products, wherein the one or more olefin(s) having been made byconverting an alcohol, particularly methanol, using a zeolite orzeolite-type molecular sieve catalyst composition. The preferredpolymerization process is a gas phase polymerization process and atleast one of the olefins(s) is either ethylene or propylene, andpreferably the polymerization catalyst system is a supported metallocenecatalyst system. In this embodiment, the supported metallocene catalystsystem comprises a support, a metallocene or metallocene-type compoundand an activator, preferably the activator is a non-coordinating anionor alumoxane, or combination thereof, and most preferably the activatoris alumoxane.

Polymerization conditions vary depending on the polymerization process,polymerization catalyst system and the polyolefin produced. Typicalconditions of polymerization pressure vary from about 100 psig (690kPag) to greater than about 1000 psig (3448 kPag), preferably in therange of from about 200 psig (1379 kPag) to about 500 psig (3448 kPag),and more preferably in the range of from about 250 psig (1724 kPag) toabout 350 psig (2414 kPag). Typical conditions of polymerizationtemperature vary from about 0° C. to about 500° C., preferably fromabout 30° C. to about 350° C., more preferably in the range of fromabout 60° C. to 250° C., and most preferably in the range of from about70° C. to about 150° C. In the preferred polymerization process theamount of polymer being produced per hour is greater than 25,000 lbs/hr(11,300 Kg/hr), preferably greater than 35,000 lbs/hr (15,900 Kg/hr),more preferably greater than 50,000 lbs/hr (22,700 Kg/hr) and mostpreferably greater than 75,000 lbs/hr (29,000 Kg/hr).

The polymers produced by the polymerization processes described aboveinclude linear low density polyethylene, elastomers, plastomers, highdensity polyethylene, low density polyethylene, polypropylene andpolypropylene copolymers. The propylene-based polymers produced by thepolymerization processes include atactic polypropylene, isotacticpolypropylene, syndiotactic polypropylene, and propylene random, blockor impact copolymers.

Typical ethylene based polymers have a density in the range of from 0.86g/cc to 0.97 g/cc, a weight average molecular weight to number averagemolecular weight (M_(w)/M_(n)) of greater than 1.5 to about 10 asmeasured by gel permeation chromatography, a melt index (I₂) as measuredby ASTM-D-1238-E in the range from 0.01 dg/min to 1000 dg/min, a meltindex ratio (I₂₁/I₂) (I21 is measured by ASTM-D-1238-F) of from 10 toless than 25, alternatively a I₂₁/I₂ of from greater than 25, morepreferably greater than 40.

Polymers produced by the polymerization process are useful in suchforming operations as film, sheet, and fiber extrusion and co-extrusionas well as blow molding, injection molding and rotary molding; filmsinclude blown or cast films formed by coextrusion or by laminationuseful as shrink film, cling film, stretch film, sealing films, orientedfilms, snack packaging, heavy duty bags, grocery sacks, baked and frozenfood packaging, medical packaging, industrial liners, membranes, etc. infood-contact and non-food contact applications; fibers include meltspinning, solution spinning and melt blown fiber operations for use inwoven or non-woven form to make filters, diaper fabrics, medicalgarments, geotextiles, etc; extruded articles include medical tubing,wire and cable coatings, geomembranes, and pond liners; and moldedarticles include single and multi-layered constructions in the form ofbottles, vessels, large hollow articles, rigid food containers and toys,etc.

In addition to polyolefins, numerous other olefin derived products areformed from the olefin(s) recovered any one of the processes describedabove, particularly the conversion processes, more particularly the GTOprocess or MTO process. These include, but are not limited to,aldehydes, alcohols, acetic acid, linear alpha olefins, vinyl acetate,ethylene dichloride and vinyl chloride, ethylbenzene, ethylene oxide,cumene, isopropyl alcohol, acrolein, allyl chloride, propylene oxide,acrylic acid, ethylene-propylene rubbers, and acrylonitrile, and trimersand dimers of ethylene, propylene or butylenes.

The foregoing description of the invention including but not limited todrawing and example are intended to illustrate one or more embodimentsof the invention and are non-limiting. While the invention has beenillustrated an described herein in terms of the advantages, features,and applications disclosed, it will be apparent to a person of ordinaryskill in the art that the invention can be used in other instances.Other modifications and improvements can be made without departing fromthe scope of the invention.

1-46. (canceled)
 47. A process for making a polyolefin product from anoxygenate feed stream, the process comprising the steps of: (a)contacting the oxygenate feed stream with a molecular sieve catalyst inan oxygenate-to-olefin reactor thereby producing a first olefin streamhaving olefins selected from the group comprising ethylene, propyleneand mixtures thereof and byproducts selected from the group consistingof alkynes, dienes and mixtures thereof, wherein there is about 200 mppmor less of byproducts for every mole of olefins in the first productstream; (b) adding hydrogen to the first olefin stream, wherein the moleratio of hydrogen to byproducts in the first product stream is about1.05:1 or higher; (c) hydrogenating the first olefin stream in thepresence of a first hydrogenation catalyst producing a second olefinstream comprising prime olefins and unreacted hydrogen; (d) contactingthe second olefin stream with a second hydrogenation catalyst producinga third olefin stream, wherein the third olefin stream has about 10 mppmor less hydrogen based upon the composition of the third olefin stream;and (e) converting the prime olefins from the third olefin stream to thepolyolefin product.
 48. The process of claim 47, wherein at least aportion of the hydrogen is from a hydrogen source stream having about 98mol. % or more hydrogen based upon the composition of the hydrogensource stream.
 49. The process of claim 48, wherein a combined stream ofthe first olefin stream and the hydrogen source stream has about 500mppm or less methane based upon the composition of the combined stream.50. The process of claim 48, wherein a combined stream of the firstolefin stream and the hydrogen source stream has about 1 mppm or less CObased upon the composition of the combined stream.
 51. The process ofclaim 48, wherein a combined stream of the first olefin stream and thehydrogen source stream has about 1 mppm or less CO₂ based upon thecomposition of the combined stream.
 52. The process of claim 47, whereinfrom about 1.5 moles to about 10 moles of hydrogen are present for everymole of byproducts in the first olefin stream.
 53. The process of claim48, wherein the hydrogen source stream is from a source selected fromthe group comprising pipeline hydrogen, hydrogen from reformed naphtha,hydrogen from refinery streams, hydrogen from bottled sources, hydrogenfrom water electrolysis reactors, hydrogen from refinery streams andhydrogen from decomposition of oxygenates.
 54. The process of claim 47,wherein the first olefin stream is heated to a temperature ranging fromabout 100° F. (38° C.) to about 250° F. (121° C.)
 55. The process ofclaim 47, wherein the step of (a) hydrogenating occurs at a pressureranging from about 50 psia (344 kPaa) to about 400 psia (2760 kPaa). 56.The process of claim 47, wherein the first catalyst and second catalystare an elemental Group VIII metal catalysts.
 57. The process of claim47, wherein the first catalyst and second catalyst are elementalpalladium catalyst.
 58. The process of claim 47, wherein the firstolefin stream contains about 98 mol. % or more olefin based upon thecomposition of the first olefin stream.
 59. The process of claim 47,wherein the first olefin stream comprises about 90 mol. % or moreethylene based upon the composition of the first olefin stream.
 60. Theprocess of claim 47, wherein the byproducts include acetylene and thefirst olefin stream comprises about 50 mppm or less byproducts basedupon the composition of the first olefin stream.
 61. The process ofclaim 47, wherein the first olefin stream comprises about 90 mol. % ormore propylene based upon the composition of the first olefin stream.62. The process of claim 47, wherein the byproducts are selected fromthe group comprising methyl acetylene, propadiene and mixtures thereofand the first olefin stream comprises about 50 mppm or less byproductsbased upon the composition of the first olefin stream.
 63. The processof claim 47, wherein the temperature of the second olefin stream rangesfrom about 100° F. (38° C.) to about 250° F. (121° C.)
 64. The processof claim 47, wherein the step of (b) contacting occurs at a pressureranging from about 50 psia (344 kPaa) to about 400 psia (2760 kPaa).65-113. (canceled)